Silyl functional compound for improving flame retardant properties

ABSTRACT

The invention relates to the use of a silyl functional compound b), which silyl functional compound comprises a N—O—Si bond, for improving the flame retardant properties of a composition comprising an organic polymer a), which is one of a thermoplastic polymer or a thermoset polymer or a mixture thereof.

The present invention relates to a composition comprising an organicpolymer and a silyl functional compound comprising an N—O—Si-bond andthe use of a silyl functional compound for improving flame retardantproperties.

There is a need for thermoplastic polymer compositions having improvedflame retardant properties. Existing flame retardant compounds need tobe employed in relatively high concentrations to fulfill the desiredeffect although they are cost drivers in plastic formulations, and largeamounts of flame retardant additive may alter the properties of thepolymeric matrix material. Additionally, due to environmental and healthconcerns, it is desirable to reduce the use of toxic materials.

Examples for such flame retardant compositions are known from the stateof the art. EP 2 404 968 describes an aromatic polycarbonate resincomposition, comprising as a main resin material, an aromaticpolycarbonate resin occupying 85 to 95 wt % of the main resin materialand having a weight-average molecular weight of 37000 to 55000 inpolystyrene equivalent molecular weight, and a polystyrene resinoccupying 15 to 5 wt % of the main resin material and containing norubber component. Additionally, polyfluoroolefin resin, an organicsulfonate flame retardant, and a silicon flame retardant are added tothe resin material.

WO 98 12253 relates to a flame retardant composition comprising (A) apolymer which includes a copolymer of ethylene and at least one othercomonomer including a vinyl unsaturated polybishydrocarbylsiloxane (I);and (B) an inorganic filler comprising at least one member selected fromthe group consisting of oxides, hydroxides and carbonates of aluminium,magnesium, calcium and barium.

Flame retardant compounds are required which overcome the drawbacksmentioned above and which offer a wide range of application and may beemployed in various types of plastic formulations. The present inventionaddresses these needs. It relates to a composition having a non-toxic,highly active flame retardant compound with an excellentperformance-price ratio applicable in multiple different plasticsformulations.

The present invention covers the use of a silyl functional compound,wherein the silyl functional compound comprises a N—O—Si bond, forimproving the flame retardant properties of a composition comprising anorganic polymer a), which is one of a thermoplastic polymer or athermoset polymer or a mixture thereof.

In a different embodiment, the present invention deals with acomposition comprising a) an organic polymer and b) a silyl functionalcompound comprising a N—O—Si bond.

The organic polymer is any of a wide variety of polymeric typesincluding polyolefins, polystyrenics, polyvinylchloride, polyamides andpolyesters. For example, the polymer substrate may be selected from thegroup of resins consisting of polyolefins, thermoplastic olefins,styrenic polymers or copolymers, acrylonitrile-butadiene-styrene (ABS),polyamides, polyesters, polycarbonates and polymers which contain heteroatoms, double bonds or aromatic rings and mixtures thereof.

Another embodiment of the present invention is where the polymer isselected from the group consisting of polypropylene, polyethylene,thermoplastic olefin (TPO), high impact polystyrene, polycarbonate andpolyethylene terephthalate. The polymer substrate may also bethermoplastic polyurethane, thermoplastic elastomer,polymethylmethacrylate, rubbers, polyesters, polyacrylonitrile orpolyoxymethylene.

The thermoplastic polymer is more preferably a polyolefin likepolyethylene, polypropylene or copolymers thereof. The thermoplasticpolymer is most preferably polypropylene (PP). Polyethylene ispreferably linear low density (LLDPE), low density (LDPE) or highdensity (HDPE). Mixtures of polypropylene with polyethylene are suitablesubstrates, for example PP/HDPE, PP/LDPE and mixtures of different typesof polyethylene (for example LDPE/HDPE). Ethylene/propylene copolymersare also suitable substrates (polypropylene/polyethylene copolymers).TPOs are for instance blends of polypropylene homopolymers and impactmodifiers such as EPDM or ethylene/alpha-olefin copolymers.

Further examples of suitable thermoplastic polymers are:

Polymers of monoolefins and diolefins, for example polypropylene,polyisobutylene, polybut-1-ene, poly-4-methylpent-1-ene,polyvinylcyclohexane, polyisoprene or polybutadiene, as well as polymersof cycloolefins, for instance of cyclopentene or norbornene,polyethylene (which optionally can be crosslinked), for example highdensity polyethylene (HDPE), high density and high molecular weightpolyethylene (HDPE-HMW), high density and ultrahigh molecular weightpolyethylene (HDPE-UHMVV), medium density polyethylene (MDPE), lowdensity polyethylene (LDPE), linear low density polyethylene (LLDPE),(VLDPE) and (ULDPE).

Polyolefins, i.e. the polymers of monoolefins exemplified in thepreceding paragraph, for example polyethylene and polypropylene, can beprepared by different, and especially by the following, methods: a)radical polymerization (normally under high pressure and at elevatedtemperature). b) catalytic polymerization using a catalyst that normallycontains one or more than one metal of groups IVb, Vb, VIb or VIII ofthe Periodic Table. These metals usually have one or more than oneligand, typically oxides, halides, alcoholates, esters, ethers, amines,alkyls, alkenyls and/or aryls that may be either π- or σ-coordinated.These metal complexes may be in the free form or fixed on substrates,typically on activated magnesium chloride, titanium(III) chloride,alumina or silicon oxide. These catalysts may be soluble or insoluble inthe polymerisation medium. The catalysts can be used by themselves inthe polymerisation or further activators may be used, typically metalalkyls, metal hydrides, metal alkyl halides, metal alkyl oxides or metalalkyloxanes, said metals being elements of groups Ia, IIa and/or IIia ofthe Periodic Table. The activators may be modified conveniently withfurther ester, ether, amine or silyl ether groups.

Mixtures of the polymers for example mixtures of polypropylene withpolyisobutylene, polypropylene with polyethylene (for example PP/HDPE,PP/LDPE) and mixtures of different types of polyethylene (for exampleLDPE/HDPE).

Copolymers of monoolefins and diolefins with each other or with othervinyl monomers, for example ethylene/propylene copolymers, linear lowdensity polyethylene (LLDPE) and mixtures thereof with low densitypolyethylene (LDPE), propylene/but-1-ene copolymers,propylene/isobutylene copolymers, ethylene/but-1-ene copolymers,ethylene/hexene copolymers, ethylene/methylpentene copolymers,ethylene/heptene copolymers, ethylene/octene copolymers,ethylene/vinylcyclohexane copolymers, ethylene/cycloolefin copolymers(e.g. ethylene/norbornene like COC), ethylene/1-olefins copolymers,where the 1-olefin is generated in-situ; propylene/butadiene copolymers,isobutylene/isoprene copolymers, ethylene/vi-nylcyclohexene copolymers,ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylatecopolymers, ethylene/vinyl acetate copolymers or ethylene/acrylic acidcopolymers and their salts (ionomers) as well as terpolymers of ethylenewith propylene and a diene such as hexadiene, dicyclopentadiene orethylidene-norbornene; and mixtures of such copolymers with one anotherand with polymers mentioned above, for examplepolypropylene/ethylene-propylene copolymers, LDPE/ethylene-vinyl acetatecopolymers (EVA), LDPE/ethylene-acrylic acid copolymers (EAA),LLDPE/EVA, LLDPE/EAA and alternating or random polyalkylene/carbonmonoxide copolymers and mixtures thereof with other polymers, forexample polyamides.

Hydrocarbon resins (for example C₅-C₉) including hydrogenatedmodifications thereof (e.g. tackifiers) and mixtures of polyalkylenesand starch.

Polystyrene, poly(p-methylstyrene), poly(a-methylstyrene). Aromatichomopolymers and copolymers derived from vinyl aromatic monomersincluding styrene, a-methylstyrene, all isomers of vinyl toluene,especially p-vinyltoluene, all isomers of ethyl styrene, propyl styrene,vinyl biphenyl, vinyl naphthalene, and vinyl anthracene, and mixturesthereof

Copolymers including aforementioned vinyl aromatic monomers andcomonomers selected from ethylene, propylene, dienes, nitriles, acids,maleic anhydrides, maleimides, vinyl acetate and vinyl chloride oracrylic derivatives and mixtures thereof, for example styrene/butadiene,styrene/acrylonitrile, styrene/ethylene (interpolymers), styrene/alkylmethacrylate, styrene/butadiene/alkyl acrylate, styrene/butadiene/alkylmethacrylate, styrene/maleic anhydride, styrene/acrylonitrile/methylacrylate; mixtures of high impact strength of styrene copolymers andanother polymer, for example a polyacrylate, a diene polymer or anethylene/pro-pylene/diene terpolymer; and block copolymers of styrenesuch as styrene/butadiene/styrene, styrene/isoprene/styrene,styrene/ethylene/butylene/styrene or styrene/ethylene/propylene/styrene.Hydrogenated aromatic polymers derived from hydrogenation of polymers,especially including polycyclohexylethylene (PCHE) prepared byhydrogenating atactic polystyrene, often referred to aspolyvinylcyclohexane (PVCH). Hydrogenated aromatic polymers derived fromhydrogenation of polymers.

Graft copolymers of vinyl aromatic monomers such as styrene ora-methylstyrene, for example styrene on polybutadiene, styrene onpolybutadiene-styrene or polybutadiene-acrylonitrile copolymers; styreneand acrylonitrile (or methacrylonitrile) on polybutadiene; styrene,acrylonitrile and methyl methacrylate on polybutadiene; styrene andmaleic anhydride on polybutadiene; styrene, acrylonitrile and maleicanhydride or maleimide on polybutadiene; styrene and maleimide onpolybutadiene; styrene and alkyl acrylates or methacrylates onpolybutadiene; styrene and acrylonitrile on ethylene/propylene/dieneterpolymers; styrene and acrylonitrile on polyalkyl acrylates orpolyalkyl methacrylates, styrene and acrylonitrile on acrylate/butadienecopolymers, as well as mixtures, for example copolymer mixtures known asABS, MBS, ASA or AES polymers.

Halogen-containing polymers such as polychloroprene, chlorinatedrubbers, chlorinated and brominated copolymer of isobutylene-isoprene(halobutyl rubber), chlorinated or sulfochlorinated polyethylene,copolymers of ethylene and chlorinated ethylene, epichlorohydrin homo-and copolymers, especially polymers of halogen-containing vinylcompounds, for example polyvinyl chloride, polyvinylidene chloride,polyvinyl fluoride, polyvinylidene fluoride, as well as copolymersthereof such as vinyl chloride/vinylidene chloride, vinyl chloride/vinylacetate or vinylidene chloride/vinyl acetate copolymers.

Polymers derived from α,β-unsaturated acids and derivatives thereof suchas polyacrylates and polymethacrylates; polymethyl methacrylates,polyacrylamides and polyacrylonitriles, impact-modified with butylacrylate. Copolymers of monomers with each other or with otherunsaturated monomers, for example acrylonitrile/ butadiene copolymers,acrylonitrile/alkyl acrylate copolymers, acrylonitrile/alkoxyalkylacrylate or acrylonitrile/vinyl halide copolymers or acrylonitrile/alkyl methacrylate/butadiene terpolymers.

Polymers derived from unsaturated alcohols and amines or the acylderivatives or acetals thereof, for example polyvinyl alcohol, polyvinylacetate, polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate,polyvinyl butyral, polyallyl phthalate or polyallyl melamine; as well astheir copolymers with olefins mentioned above.

Homopolymers and copolymers of cyclic ethers such as polyalkyleneglycols, polyethylene oxide, polypropylene oxide or copolymers thereofwith bisglycidyl ethers. Polyacetals such as polyoxymethylene and thosepolyoxymethylenes which contain ethylene oxide as a comonomer;polyacetals modified with thermoplastic polyurethanes, acrylates or MBS.

Polyphenylene oxides and sulfides, and mixtures of polyphenylene oxideswith styrene polymers or polyamides. Polyurethanes derived fromhydroxyl-terminated polyethers, polyesters or polybutadienes on the onehand and aliphatic or aromatic polyisocyanates on the other, as well asprecursors thereof. Polyamides and copolyamides derived from diaminesand dicarboxylic acids and/or from aminocarboxylic acids or thecorresponding lactams, for example polyamide 4, polyamide 6, polyamide6/6, 6/10, 6/9, 6/12, 4/6, 12/12, polyamide 11, polyamide 12, aromaticpolyamides starting from m-xylene diamine and adipic acid; polyamidesprepared from hexamethylenediamine and isophthalic or/and terephthalicacid and with or without an elastomer as modifier, for examplepoly-2,4,4,-trimethylhexamethylene terephthalamide or poly-m-phenyleneisophthalamide; and also block copolymers of the aforementionedpolyamides with polyolefins, olefin copolymers, ionomers or chemicallybonded or grafted elastomers; or with polyethers, e.g. with polyethyleneglycol, polypropylene glycol or polytetramethylene glycol; as well aspolyamides or copolyamides modified with EPDM or ABS; and polyamidescondensed during processing (RIM polyamide systems).

Polyureas, polyimides, polyamide-imides, polyetherimids, polyesterimids,polyhydantoins and polybenzimidazoles. Polyesters derived fromdicarboxylic acids and diols and/or from hydroxycarboxylic acids or thecorresponding lactones, for example polyethylene terephthalate,polybutylene terephthalate, poly-1,4-dimethylolcyclohexaneterephthalate, polyalkylene naphthalate (PAN) and polyhydroxybenzoates,as well as block copolyether esters derived from hydroxyl-terminatedpolyethers; and also polyesters modified with polycarbonates or MBS.

Polycarbonates and polyester carbonates, polyketones, polysulfones,polyether sulfones and polyether ketones. Blends of the aforementionedpolymers (polyblends), for example PP/EPDM, Poly- amide/EPDM or ABS,PVC/EVA, PVC/ABS, PVC/MBS, PC/ABS, PBTP/ABS, PC/ASA, PC/PBT, PVC/CPE,PVC/acrylates, POM/thermoplastic PUR, PC/thermoplastic PUR,POM/acrylate, POM/MBS, PPO/HIPS, PPO/PA 6.6 and copolymers, PA HDPE, PAPP, PA/PPO, PBT/PC/ABS or PBT/PET/PC.

In one embodiment, the organic polymer is a thermoplastic polymer,whereas in another embodiment, the organic polymer is a thermosetpolymer.

Preferably, the composition additionally comprises one or morecrosslinking components (c). Suitable crosslinking components arepolyamines, polyisocyanates, phenolic and melamine based compounds. Theone or more crosslinking components (c) may be present in the range of0.05 to 10.00% by weight, preferably in the range of 0.05 to 8.00% byweight and more preferably in the range of 0.10 to 5.00% by weight,calculated on the weight of the components a)+b).

The composition according to the present invention further comprises asilyl-functional compound comprising an N—O—Si bond. Thesilyl-functional compound comprises at least one nitrogen atom and atleast one Si atom.

A particularly beneficial effect of the invention is that component b)may be employed in relatively low amounts and still gives a significantimprovement in fire retardant properties. Generally, component b) ispresent in the range of 0.1 to 15.0% by weight, preferably 0.1 to 10.0%by weight, calculated on the weight of the component a)+b). Even morepreferably, the silyl functional compound b) is present in the range of0.2 to 7.0% by weight and most preferably in the range of 0.2 to 5.0% byweight.

The silyl functional compound b) comprises a functional group comprisingthe N—O—Si bond, wherein the functional group may suitably have theformula (I)

wherein any one of R¹, R², R³, R⁴ and R⁵ is independently selected froman organic group and hydrogen. Preferably, any one of R³, R⁴ and R⁵ isindependently selected from an organic group.

Organic groups are functional groups of one or more atoms of distinctivechemical properties. The atoms of functional groups are linked to eachother and to the rest of the molecule by covalent bonds. Functionalgroups can also be charged or uncharged, linear or branched, cyclic oraromatic. Organic groups may comprise one or more heteroatoms,hydrocarbyl groups or mixtures thereof. The organic groups may containone or more oxygen, halogen, nitrogen, sulfur and/or phosphorous atoms,as well as single, double and/or triple bonds.

In one embodiment, R¹ is hydrogen and R² is an organic group. R² maysuitably be cyclohexyl, phenyl, acryl, t-butyl, n-hexyl, n-dodecyl.

In a different embodiment, R1-N-R2 together form a cyclic group, whereinthe cyclic group preferably has one or more substituents.

Suitable substituents may be carbon or heteroatoms as well as aromaticor cyclic groups. Moreover, in case of at least two substituents thesemay form a cyclic or aromatic group.

The cyclic group may suitably be selected from a heterocyclic aminegroup and a cyclic imide group. Examples for heterocyclic Imide groupsare phthalimide, maleimide whereas examples for cyclic amine groups arecarbazole groups.

Suitable examples of the silyl functional compound are:

The silyl functional compound b) has generally a decompositiontemperature of at least 140° C. Preferably, the decompositiontemperature is at least 170° C. (Measurement by thermogravimetricanalysis in an open platinum cup, temperature range: 30-600° C., heatingrate 10 K/min air, device:TGA Q5000 V3.17 Build 265, TA Instruments. Thedecomposition temperature is the temperature at which the weight vs.temperature curve exhibits its maximum slope.)

Furthermore, the composition may additionally comprise at least oneother flame retardant d) which is different from the silyl functionalcompound comprising a N—O—Si bond b). Suitably, the at least one flameretardant d) may be an organic flame retardant, an inorganic flameretardant or a mixture thereof.

Suitable examples for organic flame retardants which does not contain asilyl group are polytetrafluoroethylene, bismuth oxycloride, bismuthoxynitrate, bismuth oxychloride and organobromine flame retardant.

The organobromine flame retardants include any organic bromine compoundcapable of generating HBr or bromine radicals during thermaldegradation.

The organobromine flame retardants include, without limitation,tetrabromobisphenol A (TBBPA) and its derivatives such as esters,ethers, and oligomers, for example tetrabromophthalate esters,bis(2,3-dibromopropyloxy)tetrabromobisphenol A, brominated carbonateoligomers based on TBBPA, brominated epoxy oligomers based oncondensation of TBBPA and epichlorohydrin, and copolymers of TBBPA and1,2-dibromoethane; dibromobenzoic acid, dibromostyrene (DBS) and itsderivatives; ethylenebromobistetrabromophthalimide, dibromoneopentylglycol, dibromocyclooctane, trisbromoneopentanol,tris(tribromophenyl)triazine, 2,3-dibromopropanol, tribromoaniline,tribromophenol, tetrabromocyclopentane, tetrabromobiphenyl ether,tetrabromodipentaerythritol, decabromodiphenyl ether, tetrabromophthalicanhydride, pentabromotoluene, pentabromodiphenyl ether,pentabromodiphenyl oxide, pentabromophenol, pentabromophenyl benzoate,pentabromoethylbenzene, hexabromocyclohexane, hexabromocyclooctane,hexabromocyclodecane, hexabromocyclododecane, hexabromobenzene,hexabromobiphenyl, octabromobiphenyl, octabromodiphenyl oxide,poly(pentabromobenzyl acrylate), octabromodiphenyl ether,decabromodiphenyl ethane, decabromodiphenyl, brominatedtrimethylphenylindan, tetrabromochlorotoluene,bis(tetrabromophthalimido)ethane, bis(tribromophenoxy)ethane, brominatedpolystyrene, brominated epoxy oligomer, polypentabromobenzyl acrylate,dibromopropylacrylate, dibromohexachlorocyclopentadienocyclooctane,N′-ethyl(bis)dibromononboranedicarboximide, tetrabrombisphenol S,N′N′-ethylbis(dibromononbornene)dicarboximide,hexachlorocyclopentadieno- bis-(2,3-dibromo-1-propyl)phthalate,brominated phosphates like bis(2,3-dibromopropyl)phosphate andtris(tribromoneopentyl)phosphate and tris(dichlorobromopropyl)phosphite,N,N¹-ethylene-bis-(tetrabromophthalimide), tetrabromophthalic aciddiol[2-hydroxypropyl-oxy-2-2-hydroxyethyl-ethyltetrabromophthalate],vinylbromide, polypentabromobenzyl acrylate, polybrominateddibenzo-p-dioxins, tris-(2,3-dibromopropyl)-isocyanurate,ethylene-bis-tetrabromophthalimide and tris(2,3-dibromopropyl)phosphate.

Generally, the at least one other flame retardant d) may be selectedfrom an inorganic flame retardant, a brominated flame retardant, aphosphorus based flame retardant, a magnesium flame retardant and anitrogen based flame retardant.

Suitably, the at least one other flame retardant d) is an inorganicflame retardant, which is selected from aluminium trihydroxide,magnesium dihydroxide, antimony trioxide and mixtures thereof.Preferably, the at least one other flame retardant d) is a phosphorouscompound such as a phosphate ester.

The flame retardants may be naturally occurring or synthetic, and theycan be used alone or in combination with one another.

The at least one another flame retardant d) which is different from thesilyl functional compound comprising a N—O—Si bond b) may be included inits usual amount. For example, it may suitably be added such as up to30% by weight, with the exception of metal hydrates which may beincluded up to 70% by weight and fluoropolymer agents up to 1% byweight, all calculated on the weight of the sum of the components a) andb).

The components b) and d) can be premixed or added individually. They canbe added before or during polymerization or crosslinking. Suitably, atleast component b) of the composition is in a solid form, such aspellets, pastilles, flakes, granules or powder.

In another embodiment, at least component b) is suitably liquid at 23°C. and 100 kPa.

Further additives and components may be added to the composition. Thesecomponents can be included in usual amounts and depending on theintended use. Examples of such additives are pigments, colorants,fillers, dyes, plasticizers, thixotropic agents, levelling agents, UVabsorbers, metal passivators, antioxidants, lubricants, heatstabilizers, processing aids, deaerators and further polymeric andelastomeric components. These components may be included in an amount of0.01 to 5.00% by weight, calculated on the weight of the components a+b.

Furthermore, the invention deals with a process for improving the flameretardant properties of a composition comprising the steps of

-   -   Providing an organic polymer, which is a thermoplastic polymer        or a thermoset polymer or a mixture thereof    -   Providing a silyl functional compound comprising a N—O—Si bond    -   Mixing the components by applying mixing means.

The compositions of the invention can be prepared by generally knownmethods, for example by mixing the components in the form of powders,and further treating the mixed components at elevated temperature underconditions of shear, for example in a kneader or in an extruder. Theorder of mixing or addition of the components is not critical forobtaining the desired result.

EXAMPLES

Preparation of Silylamines:

TABLE 1 Educt Description N-Hydroxyphthalimide Supplier: Sigma Aldrich,CAS Nr. 524-38-9 Chloro(methyl) Supplier: Sigma Aldrich, CAS Nr.144-79-6 diphenylsilane Triethylamine Supplier: Sigma Aldrich, CAS Nr.121-44-8 Tetrahydrofuran Supplier: Sigma Aldrich, CAS Nr. 109-99-9Hexane Supplier: Sigma Aldrich, CAS Nr. 110-54-3 Uvinul 5050H Supplier:BASF, CAS Nr. 152261-33-1 Hydrogen peroxide Supplier: Sigma Aldrich, CASNr. 7722-84-1 Ascorbic acid Supplier: Sigma Aldrich, CAS Nr. 50-81-71-hydroxy-1H-pyrrole- Supplier: Fisher scientific, CAS Nr. 6066-82-62,5-dione

General Procedure to Prepare Silylamines:

Synthesis of Silylamines A and C:

Silylamines A and C were prepared using the formulation in table 2.

Xg Educt 1, Xg THF and Xg triethylamine were placed in a 2.0 literthree-necked round bottom flask equipped with mechanical stirrer anddrop funnel as well as nitrogen inlet and condenser.

The mixture was cooled down to 5-6° C. Then Xg Educt 2 were added dropwise under nitrogen atmosphere with stirring within 15 min. After theaddition was completed Xg of THF were added. The temperature was keptfor further 10 min. before it was allowed to raise to 23° C. Thestirring was continued under nitrogen atmosphere for further 2 h.

The solvent was removed from the filter cake by distillation using therotary evaporator at 45° C. and 16.0 mbar. The mixture was washed withXmL of hexane and filtered under nitrogen atmosphere.

Synthesis of Silylamine B:

Xg Educt 1, Xml THF and Xg Hydrogen peroxide were placed in a 2.0 literthree-necked round bottom flask equipped with mechanical stirrer anddrop funnel as well as nitrogen inlet and condenser. The stirring wascontinued under nitrogen atmosphere for further 24 h. A solution of Xgascorbic acid in Xml THF was added within 1 hour interval. The mixturewas heated up to 60° C. The mixture was cooled down to 5° C. Then XgEduct 2 were added dropwise under nitrogen atmosphere with stirringwithin 15 min. After the addition was completed Xml of THF were added.The temperature was kept for further 10 min. before it was allowed toraise to 23° C. The stirring was continued under nitrogen atmosphere forfurther 4 h.

The solvent was removed by distillation using the rotary evaporator. Themixture was washed with Xml of hexane and filtered under nitrogenatmosphere.

TABLE 2 Amount Amount Silyla of Educt of Educt mine 1 [g] Educt 1 2 [g]Educt 2 Comment A  10.10 N-Hydroxy- 14.71 Ph₂MeSiCl Triethylamine:phthalimide 6.26 g THF: 100 g + 23 g Hexane: 400 ml B 183.9  Uvinul5050H 14.30 Ph₂MeSiCl Triethylamine: 6.20 g THF: 100 g + 80 g Hexane:450 ml Hydrogen peroxide: 1 g Ascorbic acid: 10.71 C  7.05 1-hydroxy-14.52 Ph₂MeSiCl Triethylamine: 6.5 g 1H-pyrrole- THF: 100 g + 80 gHexane: 400 ml 2,5-dione

TABLE 3 Decomposition temperature Silylamine Decomposition temperature A247° C. B 241° C. C 218° C.

Performance Testing of Silylamines as Flame Retardant Synergists

The following examples show exemplarily the use of the Silylamines asflame retardant synergists in different plastics formulations. Theperformance of the products is compared to products, which are state ofthe art.

TABLE 4 Raw Material Description Moplen HF 501N Supplier: LyondellBasell, CAS Nr. 9003-07-0 Homo polypropylen MFR 10 g/10 min (230° C./2.16 kg nach ISO 1133-1), PCO 900 Supplier: Thor, A Flammit PCO 900,organic phosphorus compound containing 24% phosphorus, flame retardant

To show the effectivity of the Silylamines as flame retardant synergistsin plastics formulations the components A-C were used in state of theart formulations and the flame retardancy performance was tested.

General Method of Preparation for Testing Silylamines inPolyethylene-Based Formulations:

Thermoplast:

Preparation according to the formulation in table 6 and 7.

Thermoplastic polymer powder was mixed with an additional flameretardant synergist. This mixture was fed to a dosing balance of anextruder (model Coperion ZSK 18 K38). The silylamine was fed to a sideinlet of the extruder via a second dosing balance. Extrusion was carriedout using the temperature profile detailed further below and at 300 rpm.The overall capacity of the extruder was 2 kg/h. The composition leftthe extruder via a slot die (dimensions 28 mm×3 mm) and was cooled. Theextruded strings were granulated to particles having a size in the rangeof approximately 0.1 to 0.5 mm.

Temperature profiles in the extruder from polymer entry funnel to slotdie:

For polypropylene: 180° C./190° C./195° C./200° C./195° C./190° C./185°C.

Preparation of Test Specimens

Test specimen of dimension 125 mm×13 mm×3.2 mm and 125×13 mm ×1.6 mmwere prepared by injection molding, and subsequently stored at arelative humidity of 45 to 55% and a temperature of 20 to 25° C. for 24hours.

General Procedure to Test Flame Retardancy Properties in PlasticsFormulations:

Test procedure of flame retardant properties

The flame retardant properties of test specimen were determined in aUL-94 fire chamber based on DIN EN 60695-11-10. The test specimen weresecured in the sample holders of the UL-94 fire chamber. The burnerupper surface was positioned 1 cm below the lower surface of the testspecimen, the flame was positioned in a 45° angle and a heating outputof 50 W. The test specimen were exposed to the flame for 10 seconds,before removing the flame. If the test specimen extinguished by itselfwithin 10 seconds, the process was repeated until the sample burned oruntil 5 cycles were performed. For evaluation, the criteria summarizedin the table below were used. Test specimen which exhibited fireretardant properties below rating V 2 according to DIN EN 60695-11-10were marked as F. This rating was added to better distinguish theproperties. It is not part of DIN EN 60695-11-10.

TABLE 5 Rating of fire retardant properties Criteria F V0 V1 V2 Time toextinction of flame of single >30 s  10 s  30 s  30 s test specimenAccumulated time to extinction of >250 s 50 s 250 s 250 s flame of 5test specimen Time to extinction of flame plus >60 s  30 s  60 s  60 ssmoldering time of single test specimen after the second flame cycleFalling droplets or particles yes no no yes Ignition of the cottonunderlay by yes no no yes burning particles

The results are summarized in the tables below. The amounts are given inparts by weight (pbw). Comparative Examples are marked with an *.

TABLE 5 Amount of Further Amount of further flame flame Amount of UL 94Example Silylamine Silylamine retardant retardant Polymer Polymerclassification thickness 1* — — — — 100 Polypropylen F 3.2 mm (Moplen HF501N) 2* — — 10 PCO 900 100 Polypropylen F 3.2 mm (Moplen HF 501N) 3* —— 10 PCO 900 100 Polypropylen F 1.6 mm (Moplen HF 501N) 4  2 A 10 PCO900 100 Polypropylen V0 1.6 mm (Moplen HF 501N) 5  2 B 10 PCO 900 100Polypropylen V0 3.2 mm (Moplen HF 501N) 6  2 C 10 PCO 900 100Polypropylen V0 1.6 mm (Moplen HF 501N)

It can be concluded that the addition of silyl-functional compoundscomprising a N—O—Si bond significantly improves the flame retardantproperties of the polymer compositions according to the invention.

1. A process of preparing a flame retardant composition, the processcomprising: mixing an organic polymer component and an amount of a silylfunctional component sufficient to impart a flame retardant property tothe flame retardant composition, the organic polymer component includingone or more of a thermoplastic polymer and a thermoset polymer, and thesilyl functional component including a compound comprising a N—O—S bond.2. The process according to claim 1, further comprising mixing one ormore crosslinking components with the organic polymer component and thesilyl functional component.
 3. The process according to claim 1, whereinthe amount of the silyl functional component is in a range of 0.1 to15.0% by weight, based on the total weight of the organic polymercomponent and the silyl functional component.
 4. The process accordingto claim 1, wherein the compound comprises a functional group comprisingthe N—O—Si bond, wherein the functional group has the formula (I)

wherein R¹, R², R³, R⁴ and R⁵ independently represent an organic groupor a hydrogen atom.
 5. The process according to claim 4, wherein R¹ is ahydrogen atom and R² is an organic group.
 6. The process according toclaim 4, wherein R¹—N—R² together form a cyclic group.
 7. The processaccording to claim 6, wherein the cyclic group is selected from aheterocyclic amine group and a cyclic imide group.
 8. The processaccording to claim 4, wherein the compound comprises a plurality offunctional groups having the formula (I).
 9. The process according toclaim 1, wherein the compound has a decomposition temperature of atleast 140° C.
 10. The process according to claim 1, further comprisingmixing at least one other flame retardant with the organic polymercomponent and the silyl functional component, the at least one otherflame retardant being different from compound.
 11. The process accordingto claim 10, wherein the at least one other flame retardant includes anyone or more of an inorganic flame retardant, a brominated flameretardant, a phosphorus based flame retardant, a magnesium flameretardant and a nitrogen based flame retardant.
 12. The processaccording to claim 11, wherein the at least one other flame retardantincludes one or more of aluminum trihydroxide, magnesium dihydroxide,and antimony trioxide.
 13. A process of preparing a flame retardantcomposition, the process comprising: providing an organic polymercomponent including one or more of a thermoplastic polymer and athermoset polymer, providing a silyl functional component including acompound comprising a N—O—Si bond, and mixing the organic polymercomponent and the silyl functional component.
 14. The process accordingto claim 1, wherein the amount of the silyl functional component is in arange of 0.1 to 10.0% by weight, based on the total weight of theorganic polymer component and the silyl functional component.
 15. Theprocess according to claim 6, wherein the cyclic group has one or moresubstituents.
 16. The process according to claim 6, wherein the cyclicgroup comprises a carbazole group or phthalimide.